Traditionally, the reluctance type electric motor has been capable of providing large output torque but involved increased applied voltage. For example, even the applied voltage of a reluctance type electric motor of 100 watt output was 100 volts or over.
In an example of such traditional reluctance type electric motor of above, if the applied voltage is low of about 20 volts for example, the speed of rotation was reduced and the utility was lost.
Further, the speed was lowered, and if the speed was increased, then the efficiency was considerably deteriorated.
In other words, the magnetic path of the excitation coil of the reluctance type electric motor is closed by the magnetic pole and the salient pole, so that the inductance of the excitation coil of the reluctance type electric motor is considerably larger than that of the armature coil of well-known magnet armature.
Therefore, the output torque increases. However, because it takes time to accumulate and to discharge the magnetic energy that is accumulated in the excitation coil, the reduced torque and the counter torque result because the width between the leading edge and the falling portion of the excitation current increases.
Therefore, the speed of rotation of the motor is reduced extremely. There is no means but to increase the applied voltage in order to obtain high efficiency at high motor speed rotation. An object of the present invention is therefore to provide a highly efficient reluctance type electric motor which turns at high speed on the low applied voltage.